U.S. patent application number 14/998489 was filed with the patent office on 2017-12-07 for lighting device using short thermal path cooling technology and other device cooling by placing selected openings on heat sinks.
The applicant listed for this patent is Greentech LED. Invention is credited to Frank A. Bilan, Nhien Trang.
Application Number | 20170352605 14/998489 |
Document ID | / |
Family ID | 60483503 |
Filed Date | 2017-12-07 |
United States Patent
Application |
20170352605 |
Kind Code |
A1 |
Bilan; Frank A. ; et
al. |
December 7, 2017 |
Lighting device using short thermal path cooling technology and
other device cooling by placing selected openings on heat sinks
Abstract
A novel heat sinking technology, uniquely adaptive to LED
lighting devices in a generally LED array format containing
multiple openings on said heat sink's base portions and optionally
fin portions providing "short path cooling" technology. The "short
path cooling" technology is thoroughly taught with multiple
examples. Also taught, are methods of heat sink area maintenance
when said openings are placed on said heat sinks. Indeed, even
surface area increases are shown to be possible when multiple
openings are placed on said heat sinks. Lastly, other non-LED
semiconductor cooling is discussed and illustrated in various
figures using said "short path cooling" technology.
Inventors: |
Bilan; Frank A.; (Victor,
CA) ; Trang; Nhien; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Greentech LED |
San Jose |
CA |
US |
|
|
Family ID: |
60483503 |
Appl. No.: |
14/998489 |
Filed: |
January 12, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21V 29/83 20150115;
H01L 23/3672 20130101; F21V 29/506 20150115; F21W 2131/40 20130101;
H01L 2924/00014 20130101; F21V 21/08 20130101; F21V 29/89 20150115;
H01L 2224/48091 20130101; H01L 2224/48091 20130101; F21V 29/507
20150115; F21Y 2115/10 20160801; H01L 21/4871 20130101; F21Y
2107/00 20160801; F21Y 2105/16 20160801; F21V 29/76 20150115; H01L
2224/8592 20130101; F21V 29/75 20150115; F21K 9/232 20160801; F21V
29/763 20150115; F21S 8/06 20130101; F21S 2/005 20130101; H01L
2224/48247 20130101; F21K 9/23 20160801 |
International
Class: |
H01L 23/367 20060101
H01L023/367; F21S 2/00 20060101 F21S002/00; F21V 29/76 20060101
F21V029/76; H01L 21/48 20060101 H01L021/48; F21V 29/507 20060101
F21V029/507 |
Claims
1. A method of efficient cooling of a LED lighting device using a
heat sink having a first face and a second face with at least one
fin attached to a first side of said face wherein the said at least
one fin is exposed to the ambient environment for convective and
radiative cooling and wherein the said heat sink has a plurality of
openings of a selected shape thru the said at least one fin; and at
least one solid state light emitting device thermally and
mechanically coupled and electrically isolated to a portion of said
heat sink face, generally the second face, but not limited to said
second face wherein the cooling environment can be still air and
optionally forced air flow.
2. A method of efficient cooling using the heat sink of claim 1
wherein the LED lighting device is replaced with a solid-state
semiconductor non-light emitting but power consuming, thus heat
generating device.
3. A method of efficient cooling of a LED lighting device of claim
1 wherein at least one of the said heat sink's first face portion
can be a base portion upon which the said fin/s is/are attached and
said base portion also being allowed to contain a plurality of
openings of a selected shape thru the said heat sink second face
portion with a depth sufficient to expose the first face portion,
exposing a portion of the said heat sink's fin/s base attachment to
the said first face area/s allowing air movement in a generally
transverse manner, (but not limited to said transverse manner,
which said transverse manner may be modified by the orientation of
said heat sink) thru the said first and second face portions and
into the fin area and out into the environment with a short path
air flow and at least one solid state light emitting device
thermally and mechanically coupled and electrically isolated, to a
selected flat portion preferably, but not limited to, opposite the
fin attachment side of said heat sink, wherein the cooling
environment can be still air and optionally forced air flow.
4. A method of efficient cooling using the heat sink of claim 3
wherein the LED lighting device is replaced with a solid-state
semiconductor non-light emitting but power consuming thus heat
generating device.
5. A LED lighting device which said device consists of at least one
of a selection of solid state devices as follows: a. A silicon
based light emitting device; b. An organic based light emitting
device; which said solid state light emitting device/s can emit
light of at least one of the following colors: a. A red color as
perceived by the human eye, b. A blue color as perceived by the
human eye, c. A green color as perceived by the human eye, d. A
yellow color as perceived by the human eye, d. An ultra violet
color in the invisible range as perceived by the human eye, e. An
infra-red color in the invisible range as perceived by the human
eye, f. A mixture of red/green/blue (RGB) colors with each color
individually controllable using wired or wireless techniques, and
an optional base plug of a type selected from the following list:
a. Electrical Plug type B22d; b. Electrical Plug type E39; c. Other
electrical base plug types both custom designed or commercially
available; and an optional direct cable connection from the said
LED lighting device to an external power source when not using the
said optional base plug; and coupled to a housing, coupled to a
heat sink being thermally coupled to a thermally conductive PCB of
hybrid composition containing the said plurality of Solid State
Light Emitting Devices and wherein the said LED/s device/s are
provided with electrical power received from an external power
supply thru the said plug/cable and an external socket/cable
connection coupled to said external power supply and containing an
optional conformal coating on selected areas to protect the said
solid state lighting device from moisture, fungus and corrosion and
containing an optional transparent/translucent cover with selected
openings to allow cooling air to enter in and out of the said solid
state lighting device as freely as possible and containing an
optional hoop device for support.
6. A LED lighting device of claim 5 wherein the said base plug has
been removed and replaced with a direct cable connection from an
external power supply to the said at least one LED device/s.
7. A LED lighting device of claim 5 whose said heatsink and said
PCB have a plurality of matching openings on selected portion's of
said heat sink and correspondingly matching openings on the said
PCB mounted mechanically and thermally to said heat sink.
8. A LED lighting device which said device consists of at least one
of a selection of solid state devices as follows: a. A silicon
based light emitting device; b. An organic based light emitting
device; which said solid state light emitting device/s can emit
light of at least one of the following colors: a. A red color as
perceived by the human eye, b. A blue color as perceived by the
human eye, e. A green color as perceived by the human eye, f. A
yellow color as perceived by the human eye, d. An ultra violet
color in the invisible range as perceived by the human eye, e. An
infra-red color in the invisible range as perceived by the human
eye, f. A mixture of red/green/blue (RGB) colors with each color
individually controllable using wired or wireless techniques, and
an optional base plug of a type selected from the following list:
a. Electrical Plug type B22d; b. Electrical Plug type E39; c. Other
electrical base plug types both custom designed or commercially
available; coupled to a housing coupled to a plurality of
individual heat sinks; each having a plurality of openings thru
selected areas wherein the said openings are selected from the
following list: a. a circular shaped opening, b. a square shaped
opening, c. a polygon shaped opening, d. an elliptical shaped
opening, e. a slot shaped opening, f. an arbitrarily chosen shape
of opening; and at least one light emitting device/s which is/are
thermally and mechanically mounted and electrically isolated on
each of the said individual heat sinks and a housing coupled to a
base having a plug for electrical power which housing couples the
said individual heat sinks and their corresponding solid state
light emitting device/s in a stacked fashion into one unitized
lighting device assembly wherein the said LED devices are provided
with electrical power received from an external power supply thru
the said plug and an external socket coupled to said power supply
and containing an optional conformal coating on selected areas to
protect the said solid state lighting device from moisture, fungus
and corrosion and containing an optional transparent/translucent
cover with selected openings to allow cooling air to enter in and
out of the said solid state lighting device as freely as possible
and containing an optional hoop device for support when not using
the said optional transparent/translucent cover.
9. A LED lighting device of claim 8 wherein the said base plug has
been removed and replaced with a direct cable connection from an
external power supply to the said at least one LED device/s.
10. A LED Lighting Device comprising a plurality of individual heat
sink fins each having an L bend portion and a larger area flat
portion with a plurality of openings thru selected areas wherein
the said openings are selected from the following list: a. a
circular shaped opening, b. a square shaped opening, c. a polygon
shaped opening, d. an elliptical shaped opening, e. a slot shaped
opening, f. an arbitrarily chosen shape of opening; wherein at
least one LED lighting device is thermally and mechanically mounted
and electrically isolated on each of the said individual L bend
portions of said heat sink fins and radially mounted to a central
hub wherein the said LEDs face radially outward with respect to the
said central hub which is mounted to a center of a roughly
cylindrical/conical/half spherical housing comprising a base having
a plug for electrical power which said housing couples the said
individual heat sinks and their corresponding solid state lighting
device/s into one unitized lighting device assembly and also
containing a generally circular top portion consisting of a
thermally conductive PCB of hybrid composition containing an
additional plurality of solid state light emitting devices mounted
orthogonal to the central axis of the central hub in a radial
fashion which emit light forward axially opposite to the direction
of the base portion and having a plurality of openings also in a
radial configuration which said openings are aligned with the space
portions of the said central hub mounted L bent heat sink fins, and
which is mounted mechanically and thermally but electrically
insulative, to the most distal portion relative to the plug portion
of the solid state lighting device thus forming one unitized
lighting device assembly cylindrical in overall shape having said
LEDs on both the L bend portions and the said circular top portion
electrically connected to receive power and containing an optional
conformal coating on selected areas to protect the said solid state
lighting device from moisture, fungus and corrosion and containing
an optional transparent/translucent cover with selected openings to
allow cooling air to enter in and out of the said solid state
lighting device as freely as possible.
11. A LED Lighting Device of claim 10 wherein the base portion and
housing areas contains a power supply.
12. A high power LED lighting device having a weather and rain
water sealed power supply and a plurality of high power LED devices
mounted on a high thermally conductive heat sink base portion
having a first face and a second face with a dimension greater than
10 inches in diameter if round, and 64 square inches if
perimetrical in shape wherein a said first side has a plurality of
fins in selected areas while the said second side is a generally
flat face but can also have selected portions manifesting fins and
wherein the plurality of fins are exposed to the ambient
environment wherein the said heat sink base has a plurality of
openings of a selected shape thru the said heat sink base portion
with the said openings being of sufficient depth and width to
expose a portion of the said heat sink's fins attachment base
portions wherein the cooling environment can be ambient short path
air flow and optionally forced air flow and wherein the heat sink
openings are made to maintain a heat sink exposed surface area with
a selection of at least one of the following specifications: a.
Maintains approximately the same said heat sink fin area but allow
short path cooling air movement, b. Increases the said heat sink
fin area to allow short path cooling air movement, and wherein the
LED mounting PCB is made of copper in optional combination with
other materials such as diamond particles, allotropes of carbon
etc. and has a high thermal conductivity, possibly exceeding pure
copper and having an optional transparent cover and rain water
proofing over the LED portion.
13. A high power LED lighting device of claim 12 wherein the
heatsink/LED assembly is made of multiple modular units fastened
with removable capability into one unit and having optional
individual power supplies for each modular unit for purposes of
easy field repair and light operational redundancy.
14. A heat sinking apparatus consisting of a base plate portion
having a relatively large area top and bottom side and relatively
small area edge thickness sections and which said base portion can
be made in a shape selected from the following list: a. A square
plate, having a first side and a second side, b. A rectangular
plate, having a first side and a second side, c. A round plate,
having a first side and a second side, d. An arbitrarily chosen
shape plate, having a first side and a second side, with a
plurality of fins preferably orthogonally oriented, but not limited
to said orthogonal orientation, attached to the said top plate
section and optionally to the bottom plate section wherein the said
base portion contains selected openings with a depth sufficient to
expose a portion of the said fins' attachment point to the said
base plate to allow the flow of a cooling medium transversely thru
the said base portion from a first side of said base portion to a
second side of said base portion and thus pass over at least some
of the said plurality of said fins in a relatively short thermal
path manner.
15. A heat sinking fin which said fin can be made in a shape
selected from the following list: a. A square fin, having a first
side and a second side, b. A rectangular fin, having a first side
and a second side, c. A round fin, having a first side and a second
side, d. A "D" shaped fin with an "L" bend portion on the flat side
of the "D", having a first side and a second side, e. An
arbitrarily chosen shape fin, having a first side and a second
side, f. An arbitrarily chosen shape fin, having a first side and a
second side and at least one "L" bend portion on a chosen section
of said arbitrarily chosen shape fin having a first side and a
second side, with a plurality of openings thru said fins from said
first side to said second side to allow the flow of a cooling
medium thru the said fins from the said first side to the said
second side wherein the said openings are designed to maintain the
exposed fins surface area to a cooling medium according one of a
selection of the following specifications: a. An increase of the
said fin area resulting in a more efficient heat dissipation of
said fins, b. An increase of the said fin area resulting in no
change of efficiency of heat dissipation of said fin/s but allowing
better cooling medium flow for other purposes, c. An increase of
the said fin area resulting in worse efficiency of heat dissipation
of said fin/s but allowing better cooling medium flow for other
purposes, d. A decrease of the said fin area resulting in a more
efficient heat dissipation of said fin/s due to better air flow, e.
A decrease of the said fin area resulting in no change of
efficiency of heat dissipation of said fin/s but allowing better
cooling medium flow for other purposes, f. A decrease of the said
fin area resulting in worse efficiency of heat dissipation of said
fin/s but allowing better cooling medium flow for other
purposes,
16. A Heat Sinking Apparatus for solid state semiconductor/s
cooling having a base portion wherein one side has a plurality of
fins while the other side is a generally flat face and wherein the
plurality of fins are exposed to the ambient environment wherein
the said heat sink base has a plurality of openings of a selected
shape thru the said heat sink base portion with the said opening
being of sufficient depth and width to expose a portion of the said
heat sink's fins attachment base portion and at least one heat
generating device thermally coupled to a selected flat portion and
optionally other portion/s of said heat sink, wherein the cooling
environment can be ambient air flow and optionally forced air flow
and wherein the heat sink and PCB (when used in conjunction with
the said heat sink) openings are made to maintain a heat sink
exposed surface area with a selection of at least one of the
following specifications: a. Maintains approximately the same said
heat sink fin area to allow short path cooling air movement, b.
Increases the said heat sink fin area to allow better short path
cooling air movement, c. Reduces the said heat sink fin area to
allow better short path cooling air movement, d. Maintains the same
said heat sink base area to allow short path cooling air movement,
e. Reduces the said heat sink base area to allow better short path
cooling air movement,
17. A Heat Sinking Apparatus for solid state semiconductor/s
cooling having a base portion and at least one flat face and a
plurality of fins on each side of the said heat sink's base portion
exposed to the ambient environment wherein the said heat sink has a
plurality of openings of a selected shape thru the said heat sink
base portion with the said opening being thru the base portion
exposing the interstitial areas of the fins attachment point to
base portions both on the top fins and optionally bottom fins and
at least one heat generating device thermally coupled to a selected
flat portion and optionally other portion/s of said heat sink,
wherein the cooling environment can be ambient air flow and
optionally forced air flow and wherein the heat sink and PCB (when
used in conjunction with the said heat sink) openings are made to
maintain a heat sink exposed surface area with a selection of at
least one of the following specifications: a. Maintains
approximately the same said heat sink fin area to allow short path
cooling air movement, b. Increases the said heat sink fin area to
allow better short path cooling air movement, c. Reduces the said
heat sink fin area to allow better short path cooling air movement,
d. Maintains the same said heat sink base area to allow short path
cooling air movement, e. Reduces the said heat sink base area to
allow better short path cooling air movement,
18. A Heat Sinking Apparatus for efficient convective cooling
having a base portion and at least one flat face and a plurality of
fins on each side of the said heat sink's base portion exposed to a
gas/liquid wherein the said heat sink has a plurality of openings
of a selected shape thru the said heal sink base portion edge/s
with the said opening being thru the base portion edges producing a
cavitation of the said fins attachment point to base portions both
on the top fins and optionally bottom fins; allowing transverse
short path cooling medium flow to occur and at least one heat
generating device thermally coupled to a selected flat portion and
optionally other portion/s of said heat sink, wherein the cooling
environment can be ambient air flow and optionally forced air flow
and optionally liquid flow wherein the heat sink and PCB (when used
in conjunction with the said heat sink) openings are made to
maintain a heat sink exposed surface area with a selection of at
least one of the following specifications: a. Maintains
approximately the same said heat sink fin area to allow short path
cooling medium movement, b. Increases the said heat sink fin area
to allow better short path cooling medium movement, c. Reduces the
said heat sink fin area to allow better short path cooling medium
movement, d. Maintains the same said heat sink base area to allow
short path cooling medium movement, e. Reduces the said heat sink
base area to allow better short path cooling medium movement,
19. A PCB of hybrid composition containing a plurality of openings
thru selected areas wherein the said openings are selected from the
following list: a. a circular shaped opening, b. a square shaped
opening, c. a polygon shaped opening, d. an elliptical shaped
opening, e. a slot shaped opening, f. an arbitrarily chosen shape
of opening; and containing an array of LEDs which said array is
placed on said PCB on selected areas between the said openings
allowing efficient LED cooling due to multiple short path cooling
medium flow thru the said PCB in a generally transverse manner, but
not limited to said transverse manner, which said transverse manner
may be modified by the orientation of said PCB relative to cooling
medium flow.
20. A PCB of hybrid composition of claim 19 wherein a first side of
said PCB is thermally and mechanically bonded to a heat sink having
a base portion and fin/s and at least one opening thru base portion
approximately matching at least one PCB opening, while the second
side contains the said LED array/s.
Description
BACKGROUND
Field of the Invention
[0001] In a class of embodiments, the present invention is a heat
sinking technology applied, but not limited to, electrical lighting
devices, namely devices using Light Emitting Diodes (LEDs) in an
assembly with a heat sink technology that is more efficient than
current designs and thus helps keep the LEDs cooler.
[0002] In this present 21.sup.st century, with the advent of the
high brightness Light Emitting Diode (LED), these said LEDs have
begun to replace the electrically less efficient incandescent light
bulbs and fluorescent tubes. Presently, there is no such device as
a "white light" emitting semiconductor diode. Light emitting diode
chips emit an almost monochromatic light of predominantly one
wavelength or a few closely spaced wavelengths. White LEDs use blue
or ultra violet light emitting silicon chips. This blue or ultra
violet light excites a phosphor which in turn emits white light by
a process known as the Stokes shift emission. Using an appropriate
mix of phosphor types, a white light can be produced. For example a
white LED can be made that is "a warm light" or "a cool light".
This is the same as in fluorescent tube technology--obviously
so--they both use phosphors for white light emission.
[0003] Before the invention of the light emitting diode (emitting
infra-red light) manifested publicly in the form of U.S. Pat. No.
3,293,513, and a blue LED, U.S. Pat. No. 3,819,974, and eventually
a white LED, U.S. Pat. No. 5,998,925, electrical lighting was based
upon high temperature phenomena. Take for example, a white-hot
tungsten filament in the familiar domestic incandescent light bulb.
Later the fluorescent tube was developed which used high
temperature ionized gas technology to emit ultra violet light,
which in turn exited a phosphor inside the said tube, producing
white light. This is well and good. However there is a major
problem . . . .
[0004] Past light emitting devices (excepting chemical or
bio-luminescent) from the candle to the incandescent filament bulb
to the electric gaseous discharge tube etc. required a high
temperature for the light production.
[0005] This means that the said light producing devices of the past
could not tolerate a low temperature environment. Hence they were
enclosed in an insulated enclosure, generally made of a
borosilicate glass or quartz material; the candle or oil lamp being
an obvious exception since they use a fuel other than electricity
and consume oxygen. Indeed the famous Nobel Prize Laureate Irving
Langmuir improved upon the Edison incandescent light bulb by
placing a gas into the formally vacuum environment of Edison's
incandescent light bulb (U.S. Pat. No. 1,180,159). The inert gas in
Langmuir's light bulb produced an insulative effect, (see page 2
lines 30-41 and 71-74 of said patent) by reducing the heat
dissipation of the said filament, thus requiring less electrical
energy to be supplied to the said filament.
[0006] What does this mean and of what relevancy is this to the
present teaching? Very much indeed. Virtually all light fixtures in
the world from the elegant chandelier in the kings palace to the
naked light bulb deep in the underground mine do not overly concern
themselves with cooling the light fixture. In very high power light
fixtures like Hollywood film studios for example, they indeed do
cool these lights; but only to prevent these powerful light bulbs
from self-destruction due to their very high power per unit volume
design.
[0007] Now in the United States and in some other countries, two
forces have come into play:
[0008] a. The power of technology, with the invention of the LED
and
[0009] b. The power of government, with legislated mandates.
The former power has given us high brightness LEDs and the latter
power is banning mercury, a necessary ingredient in efficient
fluorescent tubes. Also electrical energy-saving mandates are being
imposed. There are literally billions of conventional light
fixtures in the United States, let alone the rest of the world. And
almost without exception, they all dissipate heat poorly. The LED
is not a high temperature light emitting device. It requires
cooling.
[0010] Indeed if one inspects the typical LED device datasheet, he
or she will discover that in some cases the light output and
electrical specification is measured at 25.degree. C., i.e. room
temperature. (Good luck engineers, at achieving this capability
while lighting up these LEDs). Basic physics teaches us that for
heat transfer to occur we must have a delta T (.DELTA.T)--a
temperature difference for heat to flow from hotter to cooler.
Therefore the typical LED, when operating, will always be about 20
to 30.degree. C. hotter than the heat sink. And then, the heat sink
must also be hotter than the ambient air.
[0011] In the business, cool LEDs live a long time, while hot LEDs
die young.
[0012] Also, the greater the .DELTA.T, the smaller is the area
required for a heatsink to dissipate a given BTU (British thermal
unit) of heat. Now therefore, common incandescent light bulbs
operate at .apprxeq.2500.degree. C., while LEDs should operate at a
silicon junction temperature of <100.degree. C. for long life.
This explains why LED chips require huge heat sinks relative to
their size.
[0013] Due to the afore mentioned government mandates, an ongoing
industry has sprung up solely for the purpose of retro-fitting the
incandescent and gaseous tube fixtures with LED based light bulbs,
tubes, arrays etc. A truly proverbial square peg forced into a
round hole, since all these conventional fixtures provide a hostile
environment to the cooling arts. This is not the case with new
building designs. The architect has a plethora of wonderful LED
light fixtures, properly designed by competent engineering
companies. But for each new building there are perhaps thousands of
older buildings let alone street lights etc. that need to be
accommodated with these new LED devices.
Definition of Terms
[0014] For the purposes of the present disclosure, the Abstract
portion of this document is to enable the public, and especially
the scientists, engineers, and practitioners in the art who are not
familiar with patent or legal terms or phraseology, to determine
quickly from a cursory inspection, the nature and essence of the
technical disclosure of the application. The Abstract is neither
intended to define the inventive concept(s) of the application,
which is measured by the claims, nor is it intended to be limiting
as to the scope of the inventive concept(s) in any way.
[0015] For the purposes of the present disclosure, the phrase "A
and/or B" means (A), (B), or (A and B).
For the purposes of the present disclosure, the phrase "A, B,
and/or C" means (A), (B), (C), (A and B), (A and C), (B and C), or
(A, B and C). The descriptions may use perspective-based
descriptions such as top/bottom, in/out, over/under and the like.
Such descriptions are merely used to facilitate the discussion and
are not intended to restrict the application of embodiments
described herein to a particular orientation.
[0016] Thru out this teaching, the term "distal" is in reference
with the object; distal being further away, while proximal would be
closer to the object.
The description may use the phrases "in an embodiment," or "in
embodiments," which may each refer to one or more of the same or
different embodiments. Furthermore, the terms "comprising",
"including", "having", and the like as used with respect to
embodiments of the present disclosure, are synonymous. The term
"coupled with", along with its derivatives, may be used herein.
"Coupled" may mean one or more of the following. "Coupled" may mean
that two or more elements are in direct physical or electrical
contact. However, "coupled" may also mean that two or more elements
indirectly contact each other, but yet still cooperate or interact
with each other, and may mean that one or more other elements are
coupled or connected between the elements that are said to be
coupled with each other. The term "directly coupled" may mean that
two or more elements are in direct contact. Unless otherwise
specified, throughout this disclosure, including in the claims, the
expressions "LED" denotes a light emitting diode or other solid
state device generally emitting a white light. It can also refer to
a red, green, blue, orange or yellow light emitting diode. It can
also refer to an RGB multi-chip diode assembly (RGB denotes a
red/green/blue diode assembly in one package or three individual
said diodes close together, capable of emitting each of its colors
separately or all three together, simulating white light at a
distance).
[0017] Unless otherwise specified, throughout this disclosure,
including in the claims, the expressions "OLED" (Organic Light
Emitting Diode) denotes a light emitting device creating light with
organic based technology rather than silicon semiconductor based
technology. It is presently used in some cell phones. It can also
refer to a red, green, blue or yellow OLED. It can also refer to an
RGB OLED device. (RGB denotes a red/green/blue OLED device).
The term "tube" refers to a fluorescent tube or other gaseous light
source; for example a low pressure sodium lamp etc.
[0018] The term "plug" or "base plug" generally refers to a
lighting devices bottom end piece having an electrical connector
for plugging onto an electrical socket. A similar example would be
the common light bulb with the base having a plug that engages to
an electrical light socket.
[0019] The term "top" or "bottom" of a LED lighting device
generally refers to the opposite end of the said lighting device's
base plug. A similar example would be the common light bulb with
the base being the bottom and the bulb being the top.
[0020] In this teaching, the expression "hoop device" is generally
a support device for long LED lighting devices such as depicted in
FIGS. 1-13. These devices are generally necessary when used in
horizontal or angular light fixtures as a second support. These
said hoop devices can be a half hoop device with two end-clip hooks
or can also be full hoops with the clip hooks placed internally at
180.degree. apart.
[0021] In this teaching, the expression "PCB" denotes a printed
circuit board generally bonded to a thin metal cladding. The
printed circuit board itself is extremely thin, in the order of
0.005 inches or so and is a very poor conductor of heat, about 0.25
W/mK, (where W is watts of power, m is in square meters thru which
the heat is conducting and K is the temperature difference in
degrees Kelvin) hence the extreme thinness used. The said thin PCB
is chemically bonded to an aluminum substrate, a good conductor
with a thermal conductivity of about 140-201 W/mK (depending on
alloy) or in high power applications, copper, whose thermal
conductivity is about 430 W/mK whose thickness is substantially
greater. The said metal substrate thickness can be as thin as 0.02
inches to 0.25 inches or more.
[0022] Furthermore, the expression "PCB" can also denote a printed
circuit on a nonmetallic substrate such as ceramic which is
available in a number of varieties and thermal conductivities. For
example the military and aerospace industry has used beryllium
oxide (BeO) ceramic material for years. It has a high thermal
conductivity, but is poisonous and very expensive.
[0023] Unless otherwise specified, "PCB of hybrid composition" is a
PCB consisting of copper traces electrically insulated from a base
material such as copper, aluminum, various ceramic powders or other
highly thermally conductive materials. It is termed a hybrid
printed circuit board because it is constructed of a mixture of
different materials.
[0024] Unless otherwise specified, the terms "heat sink" or "heat
sinks" throughout this teaching refer to a relatively large surface
area device that transfers conducted heat from a relatively very
small area LED or other semiconductor heat source attached to the
said heat sink device which then dissipates the said heat to the
ambient air thru the process of convection and radiation. These
said heat sinks are generally made of a selected metal or metal
alloy, but are not limited to these. Plastic/composite and selected
allotropes of carbon known as graphene having an anisotropic
thermal characteristic are also possible. To summarize, the said
heat sinks accept conducted heat and then dissipate the said heat
to the ambient atmosphere by convection and radiation.
[0025] The term "hole" or "holes" or "opening" as used on a heat
sink or PC is defined as a generally but not limited to an
essentially circular opening thru a material usually but not
limited to metal. It may be drilled, milled, punched, pierced, cut
with a laser etched or molded etc. It does not necessarily need to
be perfectly round, but can be square, hexagonal or other shape/s.
For example, laser cutting or chemical etching may produce various
shape/s of polygon, star, cross etc.
[0026] The term "slot" or "slots" as used on a heat sink is defined
as a generally but not limited to a perimetrical, essentially
oblong/rectangular opening thru a material usually but not limited
to metal. It may be punched, milled, cut with a laser etched or
molded etc. It does not necessarily need to be a perfect rectangle
but can have round ends such as an end mill would make, or can be
square ended such as a metal punch would produce. For example,
laser cutting or chemical etching can produce a variety of shapes
of slots such as straight, curved, arced etc. Additionally, the
said slots do not need to be full slots in the sense that the said
slots consists of two long sided and correspondingly two short
sides; the said slots can have two long sides and only one short
side. For example, a slot can be cut into a heatsink fin and
continue to be cut until it cuts thru the fins top (top being the
distal point from the base of the heat sink where the fin is
attached) thus producing an open ended slot.
[0027] Unless otherwise directly or indirectly or by context
defined, the expression "L bend" refers to a generally 90.degree.
bend in a thin fin used on heat sinks. (The term 90.degree. means
exactly that--within the accuracy limits of standard industry
practice. The intent of this teaching and in the claims is that
90.degree. is in fact a variable, dependent on the accuracy of the
industry practice.) The said "L bend" can also be greater or less
than 90.degree., depending on design requirements. The "L" bent
section width and angle is selected by the designer.
[0028] Unless otherwise directly or indirectly or by context
defined, the expression "first side" and "second side" of a heat
sink's base portion or fin portion refers to a heatsinks base or
fin large area sections and not to their edge portions.
[0029] Unless otherwise directly or indirectly or by context
defined, the expression "cooling medium" is generally ambient air,
but can be other gas/gasses or liquids. The said cooling medium can
be forced flow or non-forced flow.
[0030] The term "maintains surface area" or "surface area
maintaining" as used in this teaching and/or the claims means the
removal of heat sink material to produce selected holes, slots or
other shape openings such that the total heat sink area exposed to
air or other cooling gasses or liquids is not substantially
reduced. For example, the reduction in said heat sink surface area
can be allowed to be as high as 30% to 50% or more if it produces a
more efficient heat sink due to better air or other gas or liquid
flow thru said heat sink. But generally it is an ideal goal to
either maintain the same said surface area of said heat sink or to
even increase the said area by a technique taught in this
disclosure.
[0031] A deliberate reduction in said surface area may be desired
to allow a cooling medium to flow thru more freely to cool other
items as desired. For example, an electrical apparatus in a cabinet
may have a plurality of individual heat sinks which need cooling
air coming from a first side of said cabinet and this said cooling
air has to be directed to various heat sinks in said cabinet and
then exit out thru a second side of said cabinet. Therefore,
heatsinks near the fresh air entry may need to be of lesser area
per unit watt/BTU dissipation, while heatsinks far from the said
fresh air entry may need to be of larger area per unit watt/BTU
dissipation,
The term "matching" or "PCB matching" or "heat sink matching" in
reference to holes or slots being placed on a selected area of a
PCB or a heat sink generally denotes a matched set of holes or
slots on the said pair of items (namely a PCB mated to a heat
sink). The said matching does not necessarily have to be perfect.
For example, a hole or slot on a heat sink can be larger or smaller
in dimension than on its mating PCB and vice versa. Unless
otherwise specified, the term "air", "air flow", "air cooling" etc.
generally refers to the ambient atmospheric air but is not limited
to the said ambient atmospheric air. In special cases such as for
example, the section of this teaching, "OTHER APPLICATIONS OF THE
PRESENT INVENTION", it can refer to other gasses or liquids.
[0032] The vernacular term "breathe" as used in this disclosure
refers to a heat sink or an entire LED lighting device being
designed in such a manner that allows free air to circulate in and
around the said heat sink/LED lighting device as freely as
possible, providing efficient cooling.
[0033] The terms "edge effect", "boundary layer", "Bernoulli
principle", "Langmuir's laminar flow theory" and "crowding effect"
etc. are thermodynamic terms whose definitions are available in a
variety of technical text books or other publications on the said
subject. Therefore these terms will not necessarily be defined in
this disclosure
[0034] The expression "mounted" generally applies to a fixture
affixed in its place using industry professional procedures such as
bolting, screwing, nailing, gluing, clinching, interference press
fitting, clamping etc.
[0035] The term "ballast" can refer to an inductive electrical
current limiting device or an electronic device that may perform
both current limiting and power supply functions. In special cases,
other electronic control functions may be incorporated. For
example, wired or wireless control for various functions such as
for example, Pulse Width Modulation, Pulse Frequency Modulation,
Spread Spectrum Pulse Modulation of LEDs etc. Other functions can
be included, such as ambient light sensors, occupancy sensors,
timers, wireless transmission and reception for control and status
reporting etc.
[0036] Thru out this teaching, electrical wire connections will not
be shown. They are well known to the technical art.
[0037] Unless otherwise specified, thru out this teaching, light
fixture bezels, dust covers, decorative trim etc. will not be
shown. They are also well known in the art.
BRIEF DESCRIPTION OF THE PRIOR ART
[0038] Several devices related to the present invention have been
identified during this inventor's Due Diligence Search. They are as
follows: Patent Application US 2011/0115358 by Kim discloses a LED
light bulb using side emitting LED devices.
[0039] Kim discusses a plurality of heatsinks each for a group of
LEDs. The present invention discuses a plurality of heatsinks, but
with specially designed holes or slots for better air flow.
[0040] Kim also discusses a plurality of light diffusers. The
present invention discuses only one light diffuser/light cover/dust
cover which is made with openings to allow air flow.
KIM discusses a central hollow pillar for mounting LED module units
in a stacked format. The present invention discuses a central
pillar or hub, but teaches a radial placement of a plurality of LED
modules in a radial fashion. Patent Application US 2012/0075859 by
Granado et al. discloses a LED lighting device using high power LED
assemblies.
[0041] Granado uses a large finned heat sink for cooling the LEDs.
Granado teaches a large base portion with a power connector and
complex power conversion circuitry in the said base portion. The
present invention discuses a single heat sink or a plurality of
heatsinks, but with specially designed holes or slots for better
air flow. Granado does not teach this. The present invention also
teaches a base portion with a power connector but not with the
complexity of Granado. Indeed, the present invention initially
offers the first embodiment using a base portion with no built-in
power circuits and low power LEDs and other embodiments with simple
electronic ballasts.
[0042] U.S. Pat. No. 8,952,613 to Anderson et al. teaches cooling
air entering thru a transparent cover portion to cool the covered
heatsink area of an incandescent light bulb LED replacement device.
This is an excellent start for more cooling efficiency. The present
invention discuses a heat sink and a plurality of heatsinks for a
substantially larger fixture containing fifty (50) to over two
hundred (200) individual LEDs, but with specially designed holes or
slots for better air flow. Anderson does not teach this. The
present invention also discusses an optional light diffuser/light
cover/dust cover which is made with dozens of relatively small
openings closely spaced to allow a relatively large air flow to a
much larger light fixture than the light bulb type Anderson speaks
of.
[0043] U.S. Pat. No. 8,944,669 to Chien discloses a LED lighting
device using removable LED assemblies in a track format, which said
tracks can be arranged in a plethora of differing configurations. A
wonderful patent, clearly, thoroughly thought out. However, Chien
does not teach short path heatsink cooling as does the present
invention.
[0044] U.S. Pat. No. 9,068,738 to Auyeung discloses a LED lighting
device with a heatsink having holes in the fins. This is a
well-engineered design with excellent optics for even light
distribution.
[0045] The present invention discuses a plurality of heatsinks, but
with specially designed holes or slots for better air flow.
Additionally, the present invention teaches that holes or other
openings in heat sink fins should be of a size to maintain exposed
said fin surface area. Auyeung does not; neither does he teach
openings in the base plate portion to allow short path air cooling
to occur as does the present invention.
U.S. Pat. No. 6,827,130 to Larson discloses a heat sink assembly
with holes in a closed "plenum" type of arrangement with forced air
cooling.
[0046] The present invention discuses a plurality of heatsinks, but
with specially designed holes or slots for better air flow.
Additionally, the present invention teaches that holes or other
openings in heat sink fins should be of a size to maintain exposed
said fin surface area. Larson does not teach this; neither does he
emphasize non-forced ambient air cooling for his heat sink
device.
U.S. Pat. No. 9,091,424 to Mart et al. discloses a "LED Light
Bulb"; a misnomer of sorts, but nevertheless a LED lighting device
that can be used as a track light etc. Mart discusses holes (he
calls them vents) in the front face of the lighting device that is
an integral housing and heatsink assembly. The said holes extend
thru the body of the said LED lighting device from front to back. A
fan is placed in the rear and air is forced thru the said LED
lighting device body to cool the said body. Mart teaches that for
lower power LED lighting devices a fan is not necessary.
[0047] The present invention discuses a plurality of heatsinks, but
with specially designed holes or slots for better air flow
preferably without using a fan in lighting applications due to fan
noise and fan reliability. Additionally, the present invention
teaches that holes or other openings in heat sink fins should be of
a size to maintain exposed said fin surface area. Mart does not
teach this; neither does he emphasize hole sizing or holes/slots on
heatsink fins.
[0048] Mart does state in column 4, lines 32-35: " . . . In at
least some embodiments, the number of vents is dependent on the
amount of air flow needed thru the interior of LED bulb 100 to
maintain the temperature below the predetermined threshold".
Clearly, Mart understands basic thermal engineering principles. But
he does not teach the maintaining of heat sink fin surface area.
Nor does he teach the cutting of openings to expose selected heat
sink fin base attachment areas as taught by this invention.
[0049] U.S. Pat. No. 9,039,223 to Rudd et al. discloses a LED
Lighting Fixture for high power applications such as streetlights.
Rudd discloses individual LED arrays wherein each said LED array
section is mounted on a separate heat sink and then these LED
array/heat sink assemblies are joined side by side into a plurality
of assemblies to form the desired lighting fixture.
[0050] The present invention mounts a plurality of LEDs on a
heatsink fin, and then attaches them not side by side, but one heat
sink fin in front of another to complete a desired lighting
fixture. Furthermore, slots, holes or other shaped openings are
provided in the present invention to increase the heat sinking
efficiency using short path airflow techniques Rudd does not teach
this. When using a conventional extruded aluminum heat sink, this
invention also discloses various slots or other shaped openings to
allow short path air flow which results in the said heat sink
becoming a more efficient heat dissipating unit. Rudd does not
teach this.
BRIEF DESCRIPTION OF THE DRAWINGS
[0051] In a class of embodiments, the present invention consists of
a Base Plugged Light Emitting Diode lighting device (one class of
embodiments) coupled to an efficient heat sink (another class of
embodiments). Also the same efficient heat sink technology is
disclosed for other cooling functions. (yet another class of
embodiments). The inventor understands that this disclosure could
be a teaching solely for a more efficient heat sink, However it
will become obvious that this new heat sink technology is uniquely
applicable to the cooling of LED devices due to the heat sink using
carefully designed openings for efficient cooling and in selected
embodiments using transverse slot openings on extruded heat sinks
or holes or other shaped openings etc. for non-extruded heat sinks
for efficient air flow. The inventor claims by reference other heat
sink applications such as, for example efficient cooling of non LED
semiconductor devices or liquid pipe cooling in high power
electronic devices etc. The inventor further understands that most
configurations of heat sinks do function if huge quantities of
forced air flow are impinged upon the said heat sinks. However, in
the practical world of domestic, office, laboratory, studio, etc.
lighting, forced air cooling is seldom used. This invention is
ideal for generally ambient still air cooling.
[0052] The object and features of the present invention, as well as
various other features and advantages of the present invention will
become apparent when examining the descriptions of various selected
embodiments taken in conjunction with the accompanying drawings and
term definitions in this document in which:
[0053] FIG. 1 shows a partially exploded perspective view of a
First Embodiment LED lighting device.
[0054] FIG. 2 shows an assembled perspective view of a LED lighting
device in a vertical position.
[0055] FIG. 3 shows an assembled perspective view of a LED lighting
device in a horizontal position.
[0056] FIG. 3A shows an assembled perspective view of a LED
lighting device in a vertical position.
[0057] FIG. 3B shows a magnified view of a portion of FIG. 3A
[0058] FIG. 3C shows an assembled perspective view of a LED
lighting device in a horizontal position.
[0059] FIG. 4 shows a partially exploded perspective view of a
Second Embodiment LED lighting device.
[0060] FIG. 4A shows an example PCB layout of a Second Embodiment
LED lighting device.
[0061] FIG. 5 shows an assembled perspective view of a Second
Embodiment LED lighting device.
[0062] FIG. 6 shows a perspective sectional view of a Second
Embodiment LED lighting device heat sink,
[0063] FIG. 7 shows a second perspective sectional view of a Second
Embodiment LED lighting device heat sink.
[0064] FIG. 8 shows an end view of a First Embodiment LED lighting
device heat sink.
[0065] FIG. 9 shows an end view of a Second Embodiment LED lighting
device heat sink.
[0066] FIG. 10 shows an assembled perspective view of a Third
Embodiment LED lighting device.
[0067] FIG. 11 shows a partial assembled perspective view of a
Third Embodiment LED lighting device.
[0068] FIG. 12 shows an assembled perspective view of a Fourth
Embodiment LED lighting device.
[0069] FIG. 13 shows a partial assembled perspective view of a
Fourth Embodiment LED lighting device.
[0070] FIG. 14 shows a one-section perspective view of a Fifth
Embodiment LED lighting device.
[0071] FIG. 15 shows a one-section perspective view of a Sixth
Embodiment LED lighting device.
[0072] FIG. 15A shows a one-section perspective view of a Seventh
Embodiment LED lighting device.
[0073] FIG. 15B shows a one-section perspective view of a Eighth
Embodiment LED lighting device.
[0074] FIG. 16 shows a partially exploded perspective view of a
Ninth Embodiment LED lighting device.
[0075] FIG. 17 shows an assembled perspective view of a Ninth
Embodiment LED lighting device.
[0076] FIG. 18 shows an assembled perspective view of a Tenth
Embodiment LED lighting device.
[0077] FIG. 18A shows a transparent or translucent protective
plastic cover and base as can be optionally used in said Tenth
Embodiment LED lighting device.
[0078] FIG. 19 illustrates a perspective view of a first
horizontally positioned very common heat sink.
[0079] FIG. 20 illustrates a perspective view of a Eleventh
Embodiment second horizontally positioned heat sink of the present
invention.
[0080] FIG. 21 illustrates a sectional perspective view of a second
horizontally positioned heat sink of the present invention.
[0081] FIG. 22 illustrates a perspective view of a Twelfth
Embodiment third horizontally positioned heat sink of the present
invention.
[0082] FIG. 23 illustrates a perspective view of a Thirteenth
Embodiment horizontally positioned heat sink with power LEDs of the
present invention.
[0083] FIG. 24 illustrates a perspective view of a Fourteenth
Embodiment fourth horizontally positioned heat sink of the present
invention with section E-E indicated.
[0084] FIG. 25 illustrates a perspective view of a Fourteenth
Embodiment horizontally positioned heat sink of the present
invention with section E-E shown in FIG. 24 removed and arrows F-F
indicating further view magnification in FIG. 25A.
[0085] FIG. 25A illustrates a magnified sectional view F-F of FIG.
25.
[0086] FIG. 26 illustrates a perspective view of a Fifteenth
Embodiment horizontally positioned heat sink of the present
invention showing arrows G-G.
[0087] FIG. 27 illustrates a perspective view of a Fifteenth
Embodiment horizontally positioned heat sink of the present
invention with section G-G removed.
[0088] FIG. 28 shows an assembled perspective view of an Sixteenth
Embodiment LED lighting device.
[0089] FIG. 29 shows a partial view of an Seventeenth Embodiment
LED lighting device.
[0090] FIG. 30 shows a partial magnified view of an Seventeenth
Embodiment LED lighting device.
[0091] FIG. 31 shows a partially exploded view of the LED assembly
of a Seventeenth Embodiment LED lighting device.
[0092] FIG. 32 shows a LED surface mount chip with wide angle light
emission.
[0093] FIG. 33 shows a LED surface mount chip with narrow angle
light emission.
[0094] FIG. 34 shows a power LED surface mount chip with narrow
angle light emission.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0095] The following embodiments are presented for a thorough
teaching of the present invention. To aid the reader of this
teaching, the various embodiments with their accompanying figures
will be explored seriatim in a stand-alone manner whenever
possible.
First Embodiment of the Present Invention
[0096] FIG. 1 shows a partially exploded perspective view of a LED
lighting device 1 consisting of a metal clad printed circuit board
3 with an array of LEDs 2 mounted thereon. Shown below the said
items is an extruded aluminum heat sink 9 with a generally flat
surface 4 which is mechanically attached to a housing 6 which is
attached to a bayonet base 8 containing two locating lugs 7. The
bayonet base illustrated is a type B22d. However, this teaching is
not limited to the said bayonet base. A transparent cover 3a is
also provided which can come as a transparent/translucent plastic
cover or it can have multiple perforations if air flow is needed as
will be described in subsequent descriptions of various embodiments
of the present invention. The housing 6 contains no built in
ballast. Note section A-A in said FIG. 1 for FIG. 2
description.
[0097] FIG. 2 shows an assembled perspective view of a LED lighting
device in a vertical position. We will now discuss the thermal
aspects of the heat sink 9. When the heat sink 9 begins to absorb
heat by conduction from the LEDs 2 via thermally conductive PCB 3,
thermally mounted to heat sink 9, air currents will begin to flow.
The hottest parts of the heat sink will be the internal spaces of
fins 9b, 9c, 9d and 9e located in the crowded areas of the heat
sink 9 fins. For clarity heat sink 9 fins 9b, 9c, 9d and 9e have
been cut away at section A-A in FIG. 1 to show internal air
currents 7a thru 7d. Now therefore, air currents will begin to
form, illustrated by arrows 7a, thru 7d. The reader is encouraged
to imagine these air currents as occurring not just partially
distal to the heat sink 9 fin bottoms as shown by arrows 7a thru
7d, but also very much proximal to the deep inner fin parts of the
heat sink 9 where little air current motion is going on partly due
to a crowding effect by the closely spaced heat sink 9 fins. The
reason for this is that there is no high velocity artificially
forced air movement such as provided by a fan, for example. This is
a fundamentally inefficient heat sink. Why?
[0098] High school physics teaches us that hot air rises up in
still air. So now let us imagine that air depicted by arrow 7a is
moving up between the heat sink 9 fins. It will absorb heat from
said fins. By the time it has reached the vertical level of arrow
7b, it will have heated somewhat so that that the .DELTA.T between
the heat sink 9 fins is significantly reduced.
[0099] Recollect that heat transfer is a function of temperature
difference, .DELTA.T between the heat sink 9 and the gently rising
air current 7a thru 7b. Now therefore we have a conundrum; by the
time we have the same said air current reaching arrow 7c, the said
air current is even hotter, reducing the .DELTA.T to almost
zero.
[0100] Therefore the said air current goes for a tree ride to a
level depicted by arrow 7d, doing no heat absorbing work and out
into the environment. Additionally, housing 6 hinders the entrance
of air currents at the lowest level of the heat sink 9 since it is
butted hard up against the heat sink 9, further decreasing heat
sink 9 efficiency. This has been a simplistic explanation since
there are complex air currents involved in most heat sink
operations, too complex to write here. Suffice to say, the above
teaching covers the major effects.
[0101] FIG. 3 shows an assembled perspective view of a LED lighting
device in a horizontal position. Here we have a situation much more
complex to analyze. Once again, during operation of LED lighting
device 1, heating will occur. Air proximal to the LEDs 2 and PCB 3
will absorb heat and will begin to rise, hitting a brick wall so to
speak. Said air currents 7 will be forced to bend around the
lighting device 1 as depicted by arrow 7e and up into the
environment.
[0102] Air currents in and around the heat sink 9 fins are very
complex to analyze. Air currents at 7f and 7g depict crudely these
air currents rising out of the interstitial spaces of the heat sink
9 fins. Laboratory data has shown that the heat sink 9 does indeed
do a reasonable job of heat dissipation, almost as good as in the
vertical position. One can speculate that various turbulent short
path micro-currents are here occurring in and out of the
horizontally placed heat sink 9 fins. Also air currents do not
travel along the longitudinal path depicted in FIG. 2, but rise up
perpendicularly from the heat sink fins.
[0103] Nevertheless, the present invention is a useful device
because it is inexpensive to manufacture and there is minimal pre
or post machining necessary on extruded aluminum heat sink 9. A
half hoop device with two end clip hooks made of metal or plastic
is also shown fitted to grooves 11a to act as a support when placed
in a fixture without a plastic cover as shown in FIG. 1. The said
half hoop device with two end-clip hooks can also be a full hoop
with the clip hooks placed internally at 180.degree. apart. These
half hoop or full hoop devices become very necessary when this
first embodiment light fixture is long; for example they are
presently made in 42 inch (1.07 meters) lengths. Furthermore, these
said hoop devices could be used in other similar embodiments. For
clarity of other descriptions, they will not be illustrated in
following embodiments, but are incorporated herein by
reference.
[0104] FIG. 3A shows an assembled perspective view of a First
Embodiment LED lighting device in a vertical position similar to
device illustrated in FIGS. 1 thru 3. Note that a slot 9b has been
added in the area labeled M1.
[0105] FIG. 3B shows a magnified view of area M1 of FIG. 3A. An
exemplary slot 9b has been added which cuts thru the PCB 3a and
heat sink base 4a (shown in FIG. 3a), exposing the attachment bases
of heat sink fins 9a. Air can now enter thru the slot 9b and move
over the heat sink bases 9a and on out, cooling the said heat sink
fins 9, (shown in FIG. 3a) beginning at the hottest part of the
said heat sink which is at the junction of the heat sink fin 9a and
the base 4a (shown in FIG. 3a). This is illustrated clearly in FIG.
3C.
[0106] FIG. 3C shows an assembled perspective view of a First
Embodiment LED lighting device in a vertical position similar to
device illustrated in FIGS. 1 thru 3. Note that a slot 9a has been
added, as shown in FIG. 3B. Air currents 7 can now pass right thru
the heatsink assembly at the mid-point and bring in fresh cooling
air, thus increasing the overall efficiency of the said heatsink
assembly. Laboratory experiments have proven this invention to
work. For example, adding only two of such slots as illustrated in
the previous few paragraphs resulted in an overall reduction of
heat sink temperature of approximately 10-15.degree. C. This may
seem a little, but it is not; lowering a temperature even slightly
can increase LED life substantially.
Second Embodiment of the Present Invention
[0107] FIG. 4 shows a partially exploded perspective view of a
Second Embodiment LED lighting device 10 consisting of a metal clad
printed circuit board 13 with an array of LEDs 12 mounted
transversely thereon as compared to the First Embodiment. Shown
below the said items is an extruded aluminum heat sink 19 with a
generally flat surface 14 which is mechanically attached to a
housing 16 which is attached to a bayonet base 18 containing two
locating lugs 17. The bayonet base illustrated is a type B22d.
However, this teaching is not limited to the said bayonet base. As
can be seen in FIG. 4 and subsequent figures, the LEDs 12 are now
situated transversely as compared to the First Embodiment. This is
to allow slots 24 to be cut thru printed circuit board 13 for
reasons explained hereafter. Extruded aluminum heat sink 19 with a
generally flat surface 14 now has been post machined with
transverse slots 23 in the said PCB deep enough to expose the
bottoms of the heat sink 19 fins. This embodiment illustrates an
extreme example of multiple slots for a large heat dissipating
capability.
[0108] FIG. 4A shows a view of a Second Embodiment LED lighting
device PCB layout in a partial sectional format to show traces
connecting the various LEDs. PCB 13 is shown with slots 24,
mounting holes 13b, and electrical traces 13c. PCB dimensions are
shown as an example, being 57 mm width and 407 mm length. LEDs 12
are shown with their diode symbols to the immediate right of each
LED. To the untrained eye, traces 13c are a little difficult to
see, but a PCB designer would immediately recognize them. On the
top section are pads labeled IN1 and IN2. Also D1, D2, D3, D4 are
steering diodes ensuring that the LED array always receives the
correct voltage polarity regardless of the IN1 and 1N2 power
connection polarity. This example is illustrates clearly that a
multiply slotted PCB is indeed possible and practical. The 407 mm
length PCB is only one example shown. LED array panels of this
general type have been made with lengths of up to two or three
meters.
[0109] FIG. 5 shows an assembled perspective view of a Second
Embodiment LED lighting device 10 consisting of a metal clad
printed circuit board 13 with an array of LEDs 12 mounted
transversely thereon as compared to the First Embodiment. Shown
below the said items is an extruded aluminum heat sink 19 with a
generally flat surface 14 which is mechanically attached to a
housing 16 which is attached to a bayonet base 18 containing two
locating lugs 17. The bayonet base illustrated is a type B22d.
However, this teaching is not limited to the said bayonet base.
[0110] As can be seen in FIG. 5 and subsequent figures, the LEDs 12
are now situated transversely as compared to the First Embodiment.
This is to allow slots 24 to be cut thru printed circuit board 13
for reasons explained hereafter. Extruded aluminum heat sink 19
with a generally flat surface 14 which has been post machined with
said transverse slots matching the said slots 24 in the said PCB
deep enough to expose the bottoms of the heat sink 19 fins. Slots
23 from FIG. 4 are now directly below the matching slots 24 on the
PCB. Notice that the heat dissipating area of heat sink 19 has not
been disturbed too much and there is still ample flat surface 14
left for conductive heat bonding to the PCB.
[0111] FIG. 6 shows a perspective sectional view of a Second
Embodiment LED lighting device heat sink. Sectional views B-B and
C-C will now be discussed.
[0112] FIG. 7 shows a second perspective sectional view of a Second
Embodiment LED lighting device heat sink with section B-B details.
When in an operational heated condition, the heat sink 19 will
cause air currents to flow upwards. Unlike the conditions described
in the first embodiment we now have a far more efficient air
current flow. One of the basic tenets of convective heat transfer
is short thermal paths and air velocity and turbulence. Here we
have achieved these to a reasonable degree. The air current
depicted by arrow 27 traverses right thru the slot in the PCB (24
in FIG. 5) and the slot 23 on said heat sink 19 and then passes
past the exposed fins 22 and on out. Additionally, the sharp edges
of the slots produce a variety of micro turbulent effects, aiding
in heat transfer between the air and the metal heat sink. In the
American vernacular, get the air in, grab some heat from the heat
sink and "get out of Dodge" and allow a fresh current of air to
come in and repeat the process. The inventor has dubbed this
process "Short Path Heat Transfer"
[0113] FIG. 8 shows an end view of a First Embodiment LED lighting
device heat sink.
[0114] FIG. 9 shows a sectional end view C-C of a Second Embodiment
LED lighting device heat sink. The arrows 7 and 27 speak for
themselves. In the former case as shown in FIG. 8, no air currents
7 can flow thru heat sink 9. In the latter case shown in FIG. 9,
however, air currents 27 do flow fast and free thru heat sink 19
via the slot 23 (shown with a cross hatch for easy identification),
cut into the surface 14 of heat sink 19.
Third Embodiment of the Present Invention
[0115] FIG. 10 shows an assembled perspective view of a Third
Embodiment LED lighting device 39. It consists of a plurality of
individual heat sink fins 30 with LEDs 34 mounted on the bent
portions of heat sink fins 30. The entire assembly is fastened to
housing 36, bayonet base 32 containing two locating lugs 33. The
entire heatsink and LED assemblies are fastened to the housing
using appropriate fasteners 37 and spacers 38 as shown in FIG.
10.
[0116] PCBs, will no longer be shown in further descriptions to not
overcrowd the illustrations and the cost effective manufacturing
and wiring technique will not be discussed since it is well known
in the art.
[0117] The heat sink fins 30 with their bent portion are now not
extrusions but stamped metal devices. The said stamped metal can be
the metal clad PCB material used in previous embodiments or
conventional thin sheet metal with the LEDs 34 mounted electrically
insulated from the heat sink fins 30, but thermally conductive. A
variety of techniques are known in the art. Serial/parallel
electrical connections to the LED arrays are also well known in the
art and need not be discussed herein. For example all the LEDs 34
could be solder flowed on one appropriately slotted PCB and then
the said PCB LED assembly is solder flowed to all the said
heatsinks fins 30 in one manufacturing operation using various
assembly jigs etc.
[0118] FIG. 11 shows a partial assembled perspective view of the
said Third Embodiment LED lighting device 39 of FIG. 10. Air
currents depicted by arrows 27 can be seen to flow freely cooling
each LED 34 heat sink 30 segment. This short path fast air flow
device has proven to be very efficient.
[0119] Generally each heat sink 30 segment is should be sized to
have an area of 30 to 45 square centimeters per Watt of total led
power dissipation on each heatsink fin 30 segment. This is a tall
order in many respects for a single fin. The next Fourth Embodiment
helps us out here by doubling the fin area. It is important to note
that the LEDs must be at a fairly higher temperature than the
environment for heat transfer to occur. So it is a
cool-me-if-you-can game between the LED and the thermal engineer.
Enough said; it is all in the skill of the art.
Fourth Embodiment of the Present Invention
[0120] FIG. 12 shows an assembled perspective view of a Fourth
Embodiment LED lighting device 49. It consists of a plurality of
individual heat sink fins 40 with LEDs 44 mounted on the double
bent portions of heat sink fins 40. The entire assembly is fastened
to housing 36, bayonet base 33 containing two locating lugs 33,
using appropriate fasteners and spacers (not shown). The cost
effective manufacturing and wiring technique will not be discussed
since it is well known in the art. The heat sink fins 30 with their
double bent portion are now not extrusions but stamped metal
devices. The said stamped metal can be the metal clad PCB material
used in previous embodiments or thin sheet metal with the LEDs 44
mounted electrically insulated from the double heat sink fins 30,
but thermally conductive. A number of techniques are known in the
art.
[0121] FIG. 13 shows a partial assembled perspective view of the
said Fourth Embodiment LED lighting device 41. Air currents
depicted by arrows 27 can be seen to flow freely cooling each LED
44 heat sink 40 segments. This short path fast air flow device has
proven to be very efficient. This fourth embodiment has a higher
power dissipation capability than the third embodiment due to the
double surface area of the heat sink 40.
Fifth Embodiment of the Present Invention
[0122] FIG. 14 shows a one section perspective view of a Fifth
Embodiment LED lighting device 61. It is identical to the sections
in FIG. 12 with the exception that slots 62 have been added. Now
then the neophyte will say "adding slots reduces the heat sink
area". Not so; if the slot width is the same as the heat sink fin
thickness, the area is increased by the added annular area of the
heat sink fin thickness . . . . Herein we set forth the
explanation. Let us imagine a heat sink fin that is one tenth of an
inch thick. For easy mental calculation, let's cut a rectangular
slot one tenth of an inch wide and one inch long. Now from each
side of the said fin we have removed:
(0.10.times.1.0)inches+(First side of rectangular surface)
(0.10.times.1.0)inches+(Second side of rectangular surface)=0.02
square inches
However we have exposed the inner thickness of the said fin
thus:
(0.10.times.1.0)inches+(First long thickness side of rectangular
opening)
(0.10.times.1.0)inches+(Second long thickness side of rectangular
opening)
(0.10.times.0.10)inches+(First short thickness side of rectangular
opening)
(0.10.times.0.10)inches+(Second short thickness side of rectangular
opening)=0.022 square inches
[0123] Now therefore, we have created a heat sink fin 60 which is
slightly better in area and allows more free airflow as depicted by
arrow 27. Additionally, the sharp edges of the slots produce a
variety of micro turbulent effects increasing convective heat
transfer. Moving air turbulence disrupts laminar air flow which in
turn achieves better convective heat transfer. The slot population
density is limited by the heat sink fin 60's thermal conductivity
since slotting interferes with the said fin's conductive heat
transfer. So for example, if the fin was copper, it could have
twice the number of slots as aluminum since copper has roughly two
times better heat conduction. Also slot orientation is important.
Notice that FIG. 14 shows the slots in a radial pattern. This not
an accident; this configuration allows fin 60 heat conduction to
radiate out radially and thus the slots 62 will be supplied with
ample heat from its source which is the top portion where the LEDs
44 are located.
[0124] Although the inventor demonstrates that heat sink area can
be maintained when slots, holes or other shape of openings are
properly applied, there may be other cases where a relatively small
reduction of heat sink area may be allowed if the cooling
advantages outweigh the loss of said heat sink area and are hereby
incorporated by reference. As a general note, when dealing with a
heatsink base that has fins attached to the said base, it is not
necessary to maintain the same exposed surface area of the said
base because the primary function of the base is to conduct heat to
the fins, not to dissipate the majority of the heat. This is why
the said base is usually much thicker than the fins. However when
slots, holes or other shape of openings are placed on the fins,
maintaining the surface area is important. Even so, the said slots,
holes or other shape of openings can be larger if experiment shows
that air flow is improved and heat dissipation is increased. It's
all in the art of the thermal science involved and laboratory
experimentation, and therefore these described techniques are
incorporated by reference.
Sixth Embodiment of the Present Invention
[0125] FIG. 15 shows a one section perspective view of a Sixth
Embodiment LED lighting device 71 wherein a plurality of holes have
been added instead of slots. With judicious hole 72 sizing and
number and placement of said holes, this heat sink 70 has the
greatest potential for efficient short path air circulation. Once
again arrow 27 illustrates the short path air flow.
Seventh Embodiment of the Present Invention
[0126] FIG. 15A shows a one section perspective view of a Seventh
Embodiment LED lighting device 61a wherein a plurality of openings
have been made using a metal piercing technique which does not
remove any metal such as in drilling or punching holes. Once again,
heatsink area is increased and air flow is improved. The view in
FIG. 15A is reversed for clarity. The LEDs 44 are distal, mounted
on L bend 61b, hence the dashed lines indicating their presence.
The heatsink fin 60a is pierced with a plurality of openings 62a
thru which air can circulate. When the heat sink fin 60a is pierced
by a hardened tool spike that generally is shaped like a sharp nail
point, an opening 62a is forced into the metal fin 60a.
Additionally, triangular segments 63 are also produced which once
again give rise to increased exposed surface area due to the
triangular segments 63 thickness sections. Arrow 27 illustrates air
flow thru opening 62a.
Eighth Embodiment of the Present Invention
[0127] FIG. 15B shows a one section perspective view of a Eighth
Embodiment LED lighting device 71a wherein a plurality of openings
have been made using a metal stamping technique which does not
remove any metal such as in drilling or punching holes. Once again,
heatsink area is increased and air flow is improved. The view in
FIG. 15B is reversed for clarity. The LEDs 44 are distal, mounted
on L bend 71b, hence the dashed lines indicating their presence.
The heatsink fin 70a is pierced with a plurality of openings 72a
thru which air can circulate. When the heat sink fin 70a is stamped
with a hardened stamping and partial punching tool, an opening 72a
is forced into the metal fin 70a. Additionally, bridge-like
segments 73 are also produced which once again give rise to
increased exposed surface area due to the bridge-like segments 73
thickness sections. Arrow 27 illustrates air flow thru opening
72a.
Ninth Embodiment of the Present Invention
[0128] FIG. 16 shows a partially exploded perspective view of a
Ninth Embodiment LED lighting device 59. Its purpose is to produce
a lighting device as the previous embodiments, but having an
omnidirectional light emission capability. It consists of heat sink
sections 50 with slots 51, and LEDs 56 mounted on bent portions of
said heat sinks 50 which are fastened to a central hub 55. The said
assembly is attached to a housing rim 57 which is an integral part
of housing 58 with a base bayonet 57 with two prongs 53. As in
previous illustrations, the bayonet base illustrated is a type
B22d. However, this teaching is not limited to the said bayonet
base. An LED 56 embellished end cap 68 is also shown exploded from
the fixture 59 for clarity. When assembled, the top cap 68 is edge
bonded to the plurality of heat sinks 50 using thermally conductive
epoxy or the like to thermally couple the LEDs 56 on said top cap
to the plurality of heat sinks 50. To not impede airflow, a
plurality of openings 60 is also shown. Once again, electrical
connections are not shown; they are well known in the art. The base
portion 58, 57 can contain ballast electronics which are also well
known in the art and are not illustrated.
[0129] FIG. 17 shows an assembled view of the Ninth Embodiment LED
lighting device 59. The slots 51 are carefully designed so as to
keep the heat sink area the same as discussed previously. This
Ninth Embodiment LED lighting device 59 is capable of very
efficient heat dissipation. As mentioned previously, when
assembled, the top cap 68 is edge bonded to the plurality of heat
sinks 50 using thermally conductive epoxy or the like to thermally
couple the LEDs 56 on said top cap 68 to the plurality of heat
sinks 50. A transparent perforated plastic cover is generally used
with this lighting device 69. (Not shown here, but is illustrated
in FIG. 18A).
Tenth Embodiment of the Present Invention
[0130] FIG. 18 shows an assembled view of the Tenth Embodiment LED
lighting device 69, wherein the plurality of heat sinks 70 are made
from preferably, but not limited to, perforated aluminum. The holes
61 are carefully designed so as to keep the heat sink area
substantially the same surface area as discussed previously. This
Tenth Embodiment LED lighting device 69 is capable of very
efficient heat dissipation, even better than Embodiment Nine. The
top cap 68 is edge bonded to the plurality of heat sinks 70 using
thermally conductive epoxy or the like to thermally couple the LEDs
56 on said top cap to the plurality of heat sinks 70. A transparent
perforated plastic cover is generally used with this lighting
device 69. (Shown in FIG. 18A). The said plastic cover is also
carefully designed, with little or no perforations in front of the
LEDs, and large perforations between the heat sink 70 "wings". The
top portion of the lighting device 68 is also covered by the same
said cover and slotted in the triangular region 71 between the
"star" patterned LEDs 56. The better this said lighting device can
"breathe", the cooler it will run.
[0131] FIG. 18A shows an assembled view of the Eighth Embodiment
LED lighting device 69, wherein none of the interior is shown. Only
the transparent or translucent protective plastic cover 71 and base
portion is illustrated. The said assembly is attached to a housing
rim 57 which is an integral part of housing 58 with a base bayonet
57 with two prongs 53. The cover portion 71 contains a plurality of
slots 72 designed to allow air to pass into and out of the LED
light fixture. On the top portion are shown triangular openings 73
to allow air in or out as described for the said slots. Although
slots and triangular openings are shown, this invention is not
limited to this said configuration. During manufacturing, other
constraints may apply, necessitating other types of openings and
are hereby incorporated by reference. Additionally, the portions of
the said plastic cover 71 can also have lenses molded in the areas
directly in front of each LED for further light dispersion and is
hereby incorporated by reference
Other Applications of the Present Invention
[0132] Heretofore the novel heat sink structure has been taught as
applied to LED lighting devices. Nevertheless, in order to comply
with the requirement to offer a full disclosure of the present
invention, the inventor will now illustrate an alternate
semiconductor cooling application.
[0133] FIG. 19 illustrates a perspective view of a horizontally
positioned very common heat sink 80 as used by millions of
electronic devices. It consists of a flat surface portion 88 with a
plurality of fins 89. It is predominantly made by an aluminum
extrusion process or a casting process. Mounted on the surface
portion 88 are several power dissipating semiconductor devices 87.
Under operation these devices 87 generate heat; which heat is
conductively transferred to the heat sink 80 containing a plurality
of fins 89. Air currents begin to flow as described in the
description of FIG. 3. As shown by arrow 86, rising air currents
cannot traverse thru the bottom surface 88 of heat sink 80 and
diverge around the said heat sink 80. Complex micro air currents in
and around the heat sink 80 fins 89 do a reasonable job of heat
transfer to the ambient air.
[0134] Now therefore, the well understood science of heat transfer
teaches us that still air has an extremely low thermal conductivity
of about 0.026 W/mK, depending upon altitude, barometric pressure,
humidity etc. However moving air has a much better heat transfer
capability. Subsequently deep in the central inner parts of the
heat sink 80 little air current movement is going on, hence the
inefficiency of the heat sink 80.
[0135] Now let us discuss forced air cooling of the heat sink 80.
According to Langmuir's laminar flow theory, smooth and even air
flow over a surface does not result in efficient heat transfer due
to a "boundary layer effect" wherein the air atomically close to
the surface over which the air is flowing does not move. Thus heat
transfer is radiative in nature from the surface to the moving air
close above the said surface. How do we overcome this? If we cause
the air movement to be turbulent, heat transfer is more efficient
since the turbulence disrupts the boundary layer effect to a
significantly large degree by a scrubbing action of irregular
atmospheric motion especially when characterized by up-and-down
micro current turbulence.
[0136] Air turbulence is greatly induced when air is pushed, and is
less when air is sucked thru a heat sink's fins. As explained to
this inventor by a seasoned aeronautical engineer several years
ago, air molecules are to be likened to light ping pong balls that
refuse to be pushed in the direction of the forced air, but can be
easily sucked up by a vacuum cleaner. Pushing air causes
turbulence, while sucking air tends towards smoother air flow.
[0137] Now if we introduce holes or slots in the heat sinks fins,
further subtle effects occur. For example, moving air over a hole
or slot will pull additional air thru these said slots or holes due
to the "Bernoulli effect", further causing more air flow and
turbulence due to "edge effects" thus creating better heat
transfer. One type of "edge effect" occurs when moving air over an
even surface suddenly passes over a sharp discontinuity on the said
surface such as an edge or trough or channel etc. The moving air
experiences a disruption and turbulence results, further disrupting
laminar flow and convective heat transfer is augmented.
[0138] The above has been a greatly simplified explanation since a
rigorous treatment of the subject would is beyond the scope if this
teaching.
Eleventh Embodiment of the Present Invention
[0139] FIG. 20 illustrates a perspective view of an Eleventh
Embodiment of the present invention. It consists of a horizontally
positioned heat sink 90, a flat surface portion 98 with a plurality
of fins 99. Mounted on the surface portion 98 are several power
dissipating semiconductor devices 87. Under operation these devices
87 generate heat; which heat is conductively transferred to the
heat sink 90 containing a plurality of fins 99. Air currents begin
to flow; but this time thru the heat sink 90 via slots 95 as shown
by arrow 96, past the exposed bottoms of the heat sink 90 fins 94.
Now we have a faster air movement and cool air entering at the base
of the said fins 94. This is a more efficient heat sink than the
one in FIG. 19. Section D-D is removed and the remainder depicted
in FIG. 21.
[0140] FIG. 21 illustrates a partial perspective sectional view of
a horizontally positioned heat sink 90 as used in the present
invention where the proximal section D-D depicted in FIG. 20 has
been removed. It consists of a flat surface portion 98 with a
plurality of fins 99. Mounted on the surface portion 98 are several
power dissipating semiconductor devices 87. Under operation these
devices 87 generate heat; which heat is conductively transferred to
the heat sink 90 containing a plurality of fins 99. Air currents
begin to flow; but this time thru the heat sink 90 via slots 95 as
shown by arrows 96, past the exposed bottoms of the heat sink 90
fins 94. Now we have a faster air movement and cool air entering at
the base of the said fins 94. The sectional view C-C shows the
exposed fins 94 clearly. The depth of the slots 95 is just deep
enough to expose the bottoms on the Fins 90. This is a more
efficient heat sink than the one depicted in FIG. 19. Also, as
noted earlier in these teachings, slots were shown on the heat sink
90. Holes or other shape of openings may be used depending on the
engineer's design constraints and are hereby incorporated by
reference.
[0141] As a note, the heat sinks 90 as depicted in FIGS. 20 and 21
do not have to be in a horizontal position; they are more efficient
than heat sink 80 in other orientations. In the vernacular, we have
allowed the heat sink 90 to "breathe" better.
Twelfth Embodiment of the Present Invention
[0142] FIG. 22 illustrates a Twelfth Embodiment of the present
invention. It is a perspective view of a horizontally positioned
heat sink 100 as used in the present invention. It consists of a
flat surface portion 108 with a plurality of fins 104 and a
plurality of holes 105 drilled deep enough to expose the bottoms of
fins 104. Mounted on the surface portion 108 are several power
dissipating semiconductor devices 87. Under operation these devices
87 generate heat; which heat is conductively transferred to the
heat sink 100 containing a plurality of fins 104 with holes 105.
Air currents begin to flow; but this time thru the heat sink 100
via holes 105, past the exposed bottoms of the heat sink 100 fins
104. Now we have a faster air movement and cool air entering at the
base of the said fins 104. This is a more efficient heat sink than
the one in FIG. 19. FIG. 22 also shows additional side holes 205
being added to fins 104 for more efficiency. The side holes, which
are drilled just above the base portion 106, can be drilled thru
all the fins 104 or only a selected few as desired. Once again it
is recommended that the heat sink's surface maintains the same area
or more if possible.
Thirteenth Embodiment of the Present Invention
[0143] FIG. 23 illustrates a Thirteenth Embodiment of the present
invention. It is a perspective view of a horizontally positioned
heat sink 300 with fins 304 as used in the present invention. This
is a variant of the heat sink of FIG. 23 with LED devices 387
mounted on flat surface 308. This is a useful device for non-room
lighting such as embedded lighting for industrial applications and
machine interior inspection or machine operating etc.
Fourteenth Embodiment of the Present Invention
[0144] FIG. 24 illustrates a Fourteenth Embodiment of the present
invention. It is a perspective view of a horizontally positioned
double sided heat sink 400 with fins 404 positioned on each side of
base 406. A flat base portion 407 is used to mount either power
LEDs or power semiconductors (not shown) as used in the present
invention. This is a heat sink for specialty applications. In cases
where side drilling is not desired and partial drilling of one
sided finned heatsinks is also not wanted, an alternate is now
offered. Thru-drilling in the interstitial gaps between the heat
sink fins can be done to achieve good results. The next figure will
show section E-E removed.
[0145] FIG. 25 illustrates view E-E of FIG. 26 showing holes 410
aligned with interstitial gaps between the heat sink fins 404. As
shown by arrow 410 (and dashed line at point of arrow 410 showing
hole alignment), FIG. 25A is a magnified view F-F of FIG. 25
showing the holes 412 thru base 406. Note dashed line 413
indicating alignment of holes 412 with the said interstitial spaces
between the said heatsink fins 404.
Fifteenth Embodiment of the Present Invention
[0146] FIG. 26 illustrates a Fifteenth Embodiment of the present
invention. It is a perspective view of a horizontally positioned
double sided heat sink 500 with fins 504 positioned on each side of
base portion 506. A flat portion 507 both top and bottom is used to
mount either power LEDs or power semiconductors (not shown) as used
in the present invention. This is a heat sink for higher power
dissipation capability. Holes 505 are shown. These said holes are
drilled large enough to expose the bases of fins 504, and deep
enough to expose the fins save the last fins 504a and 504b for
cosmetic purposes and not to interfere with the flat portions 507.
The next figure will show section G-G removed.
[0147] FIG. 27 illustrates the heat sink of FIG. 26 with section
G-G removed. Note the exposed fins 510 caused by the drilled holes
as described in FIG. 26. During operation, this heatsink now has
air moving in a short path straight thru the double fins 504 since
the base 506 portions have been drilled out. Air flow as
represented by arrow 596 shows this clearly. Once again it is
recommended that the heat sink's surface maintains the same area or
more if possible.
Sixteenth Embodiment of the Present Invention
[0148] FIG. 28 illustrates side view of a Sixteenth Embodiment LED
light fixture 600 of the present invention. This is a high power
luminaire as would be used in tall warehouses, lamp posts,
stadiums, school gymnasiums, etc. These exclusively use high power
LEDs and generally come in 200 watt to 500 watt units and up
units.
[0149] The illustration in FIG. 28 shows a generally circular
luminaire but is not limited to this style. A perimetrical
structure such as is used in some modern street lights and
commercial wall lights etc. is also possible.
[0150] Cooling is a massive task; as is water proofing and internal
prevention of moisture build up. The said luminaire consists of a
large one piece heatsink 640 with fins 641 and a flat base 650.
Mounted on the bottom of base 650 is a highly heat conductive (such
as copper) heat spreader 662 of special design. A plurality of high
power LEDs 660 is mounted on said heat spreader 662. A
transparent/translucent cover 670 is provided and an optional large
reflector 680 is shown.
[0151] Although the said fins 641 are shown to be on the top only,
some extra fins could also be placed on selected areas on the
bottom (not shown) side also and are hereby incorporated by
reference.
[0152] To give the reader an idea of size, the heat sink 650 can be
as large as a foot (305 mm) or more in diameter. Sitting above heat
sink 640 is a central hub section containing a power supply and
other optional devices such as, for example ambient light sensors,
wired or wireless communication devices etc., with attached "eye
Bolt" 610 for mounting purposes. Side bolts 622 are also provided
for alternate mounting methods as well.
[0153] FIG. 29 illustrates a front face view of heat sink 640 with
LED assembly. Slots 630 are milled thru base 650 shown in FIG. 28
exposing the bottom parts of heatsink 640 fins 642. Note circular
section H-H.
[0154] FIG. 30 illustrates a magnified view section H-H of FIG. 29.
Slots 630 are visible and exposed fin sections 642 are clearly
shown. Why is this heatsink efficient? The thick base 650 (FIG. 28)
conducts the intense heat flux radially outward very fast and the
fins 641 sections dissipate the said heat efficiently due to the
cooling air moving thru the slots and directly around the fins and
subsequently up into the ambient environment. The cooling air first
strikes the hottest part of the heatsink fins and then follows a
short path up and out, dragging new cooling air up with it. If even
higher power LED lighting is desired, the base portion 650 can be
made of copper which has twice the thermal conductivity of
aluminum, while the fins are still aluminum. The idea is to conduct
the heat out of the middle portion where the LEDs are located as
quickly as possible. Additionally, graphene layer/s could be added
within the base portion 650 for even faster heat conduction and is
hereby incorporated by reference.
Seventeenth Embodiment of the Present Invention
[0155] FIG. 31 illustrates a Seventeenth Embodiment of the present
invention. It is a front face view only of an alternate heat sink
and LED assembly for the luminaire shown in FIG. 28. The heatsink
of this embodiment is a six part unit, pie shaped in this
illustration, but not limited to said shape, and assembled together
as shown. One segment is shown jutting out for clarity of
description. This method of constructing the luminaire heat
sink/LED assembly is advantageous for two reasons. First we are
working with a smaller assembly and second, field replacement of
sections of the LED/heatsink assemblies is easier than working on
the whole massive unit. Indeed making each section pluggable would
make field repair easy. Additionally, each said section could have
its own smaller power supply which is cheap and adds further
redundancy to power supply reliability. If one fails, the other
five segments would still provide light. There are a variety ways
to practice this invention and are hereby incorporated by
reference.
Led Lighting Devices--Short Description
[0156] LED lighting is fast becoming as ubiquitous as the
incandescent bulb was in the last century. Worldwide, manufacturers
and lighting contractors are trampling over each other to get a
piece of the action in this business. Generally, LEDs for lighting
purposes come in three classes and two types within those classes.
[0157] Class 1--Low power LEDs--less than 1 Watt dissipation.
[0158] Class 2--High power LEDs--greater than 1 Watt dissipation.
[0159] Class 3--Very High power multi-chip LED assemblies--greater
than 10 Watts dissipation and supremely difficult to cool. The two
types in class 1 and class 2 are: [0160] 1. Wide angle luminance,
about 100-165 degrees in a scattered fashion due to a flat LED
emitting face. [0161] 2. Narrow angle luminance, about 20-60
degrees typically in a Lambertian distribution due to a molded-in
lens. Class 3 devices can be narrow angle up to about 5 watts while
higher power units use a plurality of individual chips mounted as
an array in one package with a common phosphor applied over the
entire said LED chip array and so a narrow angle is more difficult.
Indeed, multi-chip units are being made with up to 100 watts
dissipation and more. They are supremely difficult to cool with
ambient air since the small area heat flux from the multi-chip
modules is extremely high. Even solid copper heat transfer is
tenuous at best. Forced air cooling is greeted with contempt by
customers due to the noise, low reliability and dust accumulation
of fans. Dust is impinged upon heat sink fins due to the orders of
magnitude greater air flow passing over the said heat sink fins as
compared to normal non-forced air flow.
[0162] LEDs used in the present invention are mostly of the low
power type because they are individually inexpensive and are
thermally manageable. A typical fixture of the present invention
can use dozens of low power LED devices, each with less than one
watt dissipation. However, the present invention does accommodate
high power LED technology since the market demands it.
[0163] FIG. 32 illustrates a sectional view of a low power surface
mount LED 100 with wide angle characteristics. It consists of a
housing 110, a copper lead frame 111, upon which is bonded a light
emitting silicon chip 112. A wire bond 115 connects the top section
of chip 112 to the other lead 111 (left copper lead in FIG. 22). A
rather large phosphor fill 114 is provided which emits white light.
The copper leads 111 provide conductive heat transfer to a printed
circuit board (not shown) on which the LED 100 is soldered.
[0164] FIG. 33 illustrates a sectional view of a low power surface
mount LED 120 with narrow angle characteristics. It consists of a
housing 115, a copper lead frame 131, upon which is bonded a light
emitting silicon chip 132. A wire bond 134 connects the top section
of chip 132 to the other lead 131 (left copper lead in FIG. 33).
Unlike in the wide angle LED shown in FIG. 32, a relatively compact
phosphor covering 124 surrounds the chip which emits white light in
an intense almost point source configuration. A molded focusing
lens 119 is also provided. The lens 119 in combination with the
mentioned small phosphor 124 the light emission angle considerably.
The copper leads 131 provide conductive heat transfer to a printed
circuit board (not shown) on which the LED 110 is soldered.
[0165] FIG. 34 illustrates a sectional view of a power surface
mount LED 130 with narrow angle characteristics. It consists of a
housing 135, a copper lead frame 141, upon which is bonded a light
emitting silicon chip 142. A wire bond 146 connects the top section
of chip 142 to the other lead 141 (left copper lead in FIG. 34).
Unlike in the wide angle LED shown in FIG. 32, a relatively compact
phosphor covering 134 surrounds the chip which emits white light in
an intense almost point source configuration. A molded focusing
lens 129 is also provided. The lens 129 in combination with the
mentioned small phosphor 144 narrows the light emission angle
considerably. The copper leads 141 provide conductive heat transfer
to a printed circuit board (not shown) on which the LED 130 is
soldered. Additionally, a copper or other highly conductive
material slug 145 removes heat from the silicon chip directly to
the exposed bottom portion of LED 130 which can be soldered to a
PCB as well as the leads 141.
[0166] High power LEDs use a great variety of mounting methods from
large area solder flow to directly bolting to a big heatsink.
SUMMARY RAMIFICATIONS AND SCOPE
[0167] The fixtures described in this teaching provide the
installation professional several advantages, some of which are
summarized as follows:
[0168] 1. Low cost.
[0169] 2. Universal mounting positions.
[0170] 3. Minimum installation labor.
[0171] 4. Retrofit versatility.
[0172] 5. Light weight.
[0173] 6. Low power consumption.
[0174] A hidden feature of LED light fixtures is that these
fixtures can be made to produce white, red, green, blue or yellow
light. For example a yellow or red light fixture may be used in a
chemistry lab or photo processing lab where white light is not
desired. Indeed the same fixture could be made to have two or more
color LEDs so that one fixture can perform both jobs as necessary.
This was not easily done with fluorescent light fixtures of the
past. Furthermore RGB LED lights can produce a variety of colors
necessary by controlling the power to each of the three led
devices. Generally this is done using Pulse Width Modulation
techniques which will not be described here since it is well
understood in the art. These features can be controlled remotely by
Power Line Signal or Optical Signal or Radio Frequency Signal
means. They will not be described since they also are well known in
the art. These control devices are available on the commercial
market as complete modules. Most are covered by their own patent
portfolios; thus this disclosure does not claim their technology,
but does claim the use of these said control devices in the
specific environment of LED devices described herein.
[0175] RGB LEDs can also be used for white light variations such a
"warm white" for winter and a "cool white" for summer etc. ("Warm
white" is a lower color temperature tending towards the yellow
whereas a "cool white" is a higher color temperature tending
towards the blue.). None of the described embodiments showed
built-in ballasts/power supplies. Although they were not described,
the present invention does not preclude their use as a built in
device but has omitted them for clarity of the teaching
[0176] This inventor claims these aspects of the novelty and the
claims section of this patent reflect this clearly. Although the
descriptions above contain a number specificities these should not
be construed as limiting the scope of the invention but as merely
providing illustrations of some of the presently preferred
embodiments of this invention. Thus the scope of the invention
should be determined by the appended claims and their legal
equivalents rather than by the examples provided.
[0177] The claims are not limited to the various aspects of this
disclosure, but are to be afforded the full scope consistent with
the language of the claims. Structures and functional equivalents
of the elements of the various aspects described throughout this
disclosure that are known or are later come to be known to those
skilled in the art are expressly incorporated herein by reference
and are intended to be encompassed by metes and bounds of the
claims. Additionally, nothing disclosed herein is intended to be
dedicated to the public regardless of whether such disclosure is
explicitly recited in the claims. No claim element is to be
construed under the provisions of 35 U.S.C. .sctn.112, sixth
paragraph, unless the element is expressly recited using the phrase
"means for" or in the case of a method claim, the element is
recited using the phrase "step for".
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